Kapoor tweeted: "Today!!!#OkJaanu #13thJanuary ."
OK Jaanu is directed by Shaad Ali and stars Shraddha Kapoor and Aditya Roy Kapur as the lead pair.
The movie also features veteran actors Naseeruddin Shah and Leela Samson.
The story is penned by acclaimed director Mani Ratnam with score by AR Rahman.